Fig. 7. Conditional stabilization of ß-catenin by Osx1-GFP::Cre promotes premature mineralization of skeletal elements. Histological analysis and in situ hybridization of ³⁵S-labeled riboprobes to sections of E14.5 tibia from (A-I) Catnb^lox(ex3)/+ (wild type) and (J-R) Osx1-GFP::Cre;Catnb^lox(ex3)/+ (mutant) embryos, with specific anti-sense riboprobes for marker genes that identify states of chondrocyte and osteoblast differentiation. Chondrocyte: (E,N) Col21 and (F,O) Col101. Osteoblast: (G,P) Col11, (H,Q) osterix1 and (I,R) osteoprotegerin. Arrows indicate premature mineralization, identified as silver deposition by (K) von Kossa and (L) Alizarin red staining, present in mutants compared with (B,C) wild types. (S,T) Analysis of BrDU incorporation in wild-type and mutant embryos at E14.5. Graphs represent the relative number of proliferative cells within the (S) growth plates or (T) periosteal region of mutant and wild-type tibia. Error bars represent the s.d. of the mean of the results (n3).